US2085561A - Gaseous electric discharge device - Google Patents

Description

June 29, 1937. K. WlEGAND 2,085,561

GASEOUS ELECTRIC DISCHARGE DEVICE Filed April 2, 1955 INVENTOR 07W 1 JVa wf".

ATTORNEY tates. the starting of such devices.

Patented June 29, 1937 PATENT OFFICE 2,085,561 1 GASEOUS ELECTRIC DISCHARGE DEVICE Kurt Wiegand, Berlin-neu-Tempelhof, Germany,

assignor to General Electric poration of New York Company, a cor- Appllcation April 2, 1935, Serial No. 14,356 In Germany April 7, 1934 2 Claims. (Cl. 176 -122) The present invention relates to gaseouselectrio discharge devices generally and more particularly the invention relates to methods and means for starting such devices into operation.

5 A high resistance element surrounded by an insulating tube and'extending along the discharge path between the electrodes of, a gaseous electric discharge device with the ends thereof exposed and adjacent the electrodes of said device facili- Thermionic electrodes for gaseous electric discharge devices are advantageously provided with heaters, such as an electric resistance connected across the terminals of a heater current source, to rapidly l5 raise said electrodes to an electron emitting, discharge supporting temperature which facilitates the starting of the discharge in a device incorporating such electrodes.

The object of the presentinvention is to provide a simple, efilcient, self-starting gaseous electric discharge device of the type having a conducting wire extending along the discharge path therein and having a-pair of electron emitting electrodes each equipped with a heater. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description. a

In accordance with this object one end of th heater of each of the electron emitting electrodes of the new and novel discharge device is connected to a terminal of the current source for said device and the other end of said heater is connected to a cylindrical sheath of conducting material surrounding said electrode and termed hereinafter the electrode sheath. The electrically conducting element extending along the discharge path between said electrodes has fastened to each end thereof a cylindrical sheath of conducting material, termed hereinafter the auxiliary sheath, which surrounds the electrode sheath. The two sheaths, that is, the electrode sheath and the auxiliary sheath, at each end of the container are separated a distance such that a glow discharge takes place therebetween on the voltage applied thereto before the main discharge between the maln discharge supporting, electron emitting electrodes has started. During this period the heaters of said main electrodes, are connected in series across the terminals of the current source and said electrodes are rapidlyraised thereby to the electron emitting, discharge supporting temperature thereof. The electrons emitted by the electrodes and emanations from 55 the glow discharge at each end of the container at each end thereof.

quickly ionize the gaseous filling in the lamp and the main discharge starts. When said main discharge starts the voltage between the two sheaths at each end of the container drops below the maintaining voltage of the glow discharge therebetween and current fiow through the heaters is interrupted. During the'operation of the device the electron emitting electrodes are maintained at an electron emitting, discharge supporting temperature by the main discharge. incident thereat.

In the drawing accompanying and forming part of this specification an embodiment of the invention is shown in a front elevational, partly sectional View.

Referring to the drawing the new and. novel gaseous electric discharge device comprises an elongated, tubular glass container I having a gaseous atmosphere therein, such as a rare gas, a metal vapor, a mixture of gases, a mixture of metal vapors, or a mixture of gas and metal vapor. I prefer to use in such lamps a mixture of a starting gas and a metal vapor, such as a mixture of neon and sodium vapor, or argon and mercury vapor. Said container I has a main discharge supporting electrode 2, 3 sealed therein Said electrodes 2, 3 consist of a curved rod or bar 3 of electron emittin material, such as a pressed and sintered, pulverized mixture of barium oxide, strontium oxide and tungsten, and a heater wire 2, such as a tungsten filament, wrapped around said bar 3. One end of each of said heater wires 2 isconnected by a current lead 4 or II to a terminal 6 or ll! of an alternating current source for said discharge device. The lead 4 has a ballasting resistance 5 connected therein. The other end of said heater wire 2 is connected by current lead I to a cylindrical sheath 8 of conducting material surrounding said electrode 2, 3. Said sheath 8 is supported in said container I by support wire I 0 fused thereto and fused-into the pinch part 9 of the stem of said container I.

A coiled, high resistance wire I3 extends along the main discharge path in said container I and is surrounded by a tube l5 of insulating material. The ends ll of said wire I3 extend beyond the ends of the insulating tube I5 and are attached to, as by fusing, the cylindrical sheath I! which is likewise of conducting material. Said insulating tube I5, wire I3 surrounded thereby and the sheaths, I! are supported in said container I by spring supports I6 fastened adjacent'the ends of said tube l5 and pressing against the inner surface Of the container I. The two sheaths 8 and I1 are concentric and are separated a distance such that a glow discharge takes place therebetween when potential is applied across the terminals of the device.

When potential is applied to the above described device two glow discharges take place immediately between the pairs of sheaths 8 and I1. Current then flows through the heater circuit consisting of the conductor 4, the left hand heater wire 2, the left hand sheaths 8, H, the resistance wire l3, the right hand sheaths l1, 8, the right hand heater wire 2 and the conductor H. Both heater wires 2 immediately emit an intense heat to rapidly raise the rods 3 to an electron emitting, discharge supporting temperature. When the gas filling is'suificiently ionized by the flow of electrons from said electrodes 2, 3 the main discharge starts therebetween and the voltage in the heater current circuit drops below the maintaining voltage of the glow discharge between said sheaths 8 and IT. The glow discharges between the sheaths 8, I! are thus extinguished and current flow through the heater circuit is interrupted. The main electrodes 2, 3 are maintained at an electron emitting, discharge supporting temperature by the main discharge therebetween during the operation of the device.

The concentric sheaths which surround the electrodes 2, 3 reduce the radiation of heat therefrom during the operation of the device and thus serve to maintain said electrodes 2, 3 at an electron emitting, discharge supporting temperature.

While I have shown and described and have pointed out in the annexed claims certainnovel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention, for example, other types of electron emitting electrodes, such as a tungsten or nickel filamentcoated or impregnated with electron emitting material, or the well known Hull electrodes, are used in place of the electrodes 2, 3 when desired and the sheaths I! are supported in said container I by resilient means, such as spring leaves, fastened thereto and pressing against the inner surface of said container, when desired.

What I claim as new and desire to .secure by Letters Patent of the United States, is:-

1. In combination a gaseous electric discharge device comprising a tubular container, main-discharge supporting electrodes and auxiliary starting electrodes sealed therein at the ends thereof, a gaseous atmosphere therein, and an element of conducting material extending along the dising coaxial cylindrical members open in the direction of the main discharge path and being mounted in pairs at each end of the container and surrounding one of said main electrodes, a current source for said device, one end of said heater element being connected to said current source, the other end of said heater element being connected to the inner one of said auxiliary electrodes, the outer auxiliary electrode of each pair being connected to the element of conducting material extending along the discharge path in said container to fa'cilitatethe starting of the main discharge, the breakdown potential of the discharge between said auxiliary electrodes being less than the breakdown potential of discharge between said main electrode and the outer auxiliary electrode, said auxiliary electrodes reducing the heat losses from said main electrodes.

2. A gaseous electric discharge device comprising a container, a-main discharge supporting electrode sealed therein, a gaseous atmosphere therein, an auxiliary, startingelectrode mounted adjacent said main electrode,-.said. main electrode comprising a heater e1ement and.a body of material having high electron emissivity characteristics mounted in heat receiving relation to said heater element, a body of electrically conducting material interposed between said auxiliary electrode and the part of said main electrode having high electron emissivity characteristics to prevent the formation of an auxiliary, starting discharge between said main electrode and said auxiliary electrode, one end of said heater element being connected to a current lead sealed into said container, the other end of said heater element being connected to said electrically conducting body, the distance-between said auxiliary electrode and said conducting body being less than the striking distance of the potential applied to these elements during the starting of the device.

KURT WIEGAND.

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